Preparing for CAS security and Internet access

- Each of your client access servers are going to run multiple web applications, like Outlook web app, the control panel, Exchange active sync. Also the offline address book, but all these web applications are gonna have two properties. They're gonna have an internal URL, like the one shown here, and they're also gonna have an external URL as well. Let's look at the properties of the offline address book application. Go over to the URL's tab and you can see there's my internal URL, it's set the internal name of my CAD server. The external URL is what would be fed to an external client if they were accessing this via Outlook anywhere.

And this would be a publicly accessible URL, and if you're not sure what the offline address book is, it's something that the clients download in order to be able to see the Gow when they're not connected to Exchange. So if I take my laptop onto an airplane, I want to be able to compose some messages and see the users that are out there without actually being connected. And so this would be one use case for that, and when you're, next time you go online, even though you might be on the outside network you can hit this external URL and download the latest version of the offline address book. When you're on the inside network, that name space might be different and you can pull it from that URL.

So every one of these web applications has both of these properties, and you know, some of them are for Outlook anywhere, the offline address book is used primarily for that. Outlook web app also has the same set internal and external URL's. And that would be used in the same situation but also for multi-site configurations. So if you have two internet facing sites, where you have CAD servers you could populate this external URL value that way if the user hits the wrong CAD server you could direct them to the appropriate external URL.

Let's take a look at how you would set this on all these web applications at once. So in the console after you're under the server configuration under client access. And highlight your first CAD server and come over to the actions pane and click on "configure external client access". This'll bring up the wizard. And here you're gonna want to define your external name space. In my case that's gonna be "mail.interface.ttlabs.com", and then I'm going to specify the CAD servers. In my environment I've got three right now, in my primary active directory site I just have two.

So I'm gonna make sure that the CAD servers on my primary site, that's the internet facing site, I'm gonna make sure that I set the URLs on both of those servers at once. And then I'm just gonna click on this "configure" button. And a nice thing about this is that Exchange will go through every single one of those web applications, OAB, OWA, ActiveSync, Excange web services. It'll run through every single one of them and configure those settings for me. So it saves me from having to go in the shell and manually run these commands to take care of this.

Now notice that we're getting some warnings here. One particularly that comes up is "The host specified for the external URL "parameter cannot be resolved". That's because I haven't set up my DNS yet. I'm going to do that moving forward, but for now I'm just going to ingore this and say "yes to all". Now my next step would be to take this external URL value and go out to DNS, my public DNS, and make sure that I've got a record for "mail.interface.ttlabs.com". So as you can see configuring the external URL is very simple to do with the configure external client access wizard.